<template>
  <div class="scrollbar">
    <div
      ref="wrap"
      :class="[wrapClass, 'scrollbar__wrap', native ? '' : 'scrollbar__wrap--hidden-default']"
      :style="style"
      @scroll="handleScroll"
    >
      <component :is="tag" ref="resize" :class="['scrollbar__view', viewClass]" :style="viewStyle">
        <slot></slot>
      </component>
    </div>
    <template v-if="!native">
      <bar :move="moveX" :size="sizeWidth" />
      <bar vertical :move="moveY" :size="sizeHeight" />
    </template>
  </div>
</template>

<script setup lang="ts">
import { addResizeListener, removeResizeListener } from "@/utils/event";
import { toObject } from "./util";
import Bar from "./bar";
import type { CSSProperties } from "vue";

const props = defineProps({
  native: {
    type: Boolean,
    default: false
  },
  wrapStyle: {
    type: [String, Array, Object],
    default: ""
  },
  wrapClass: {
    type: [String, Array, Object],
    default: ""
  },
  viewClass: {
    type: [String, Array, Object],
    default: ""
  },
  viewStyle: {
    type: [String, Array, Object],
    default: ""
  },
  noresize: Boolean, // 如果 container 尺寸不会发生变化，最好设置它可以优化性能
  tag: {
    type: String,
    default: "div"
  }
});

const sizeWidth = ref("0");
const sizeHeight = ref("0");
const moveX = ref(0);
const moveY = ref(0);
const wrap = ref();
const resize = ref();

provide("scroll-bar-wrap", wrap);

const style = computed<CSSProperties | string>(() => {
  if (Array.isArray(props.wrapStyle)) {
    return toObject(props.wrapStyle) as CSSProperties;
  }
  return props.wrapStyle;
});

const handleScroll = () => {
  if (!props.native) {
    moveY.value = (unref(wrap)?.scrollTop * 100) / unref(wrap)?.clientHeight;
    moveX.value = (unref(wrap)?.scrollLeft * 100) / unref(wrap)?.clientWidth;
  }
};

const update = () => {
  if (!unref(wrap)) return;

  const heightPercentage = (unref(wrap).clientHeight * 100) / unref(wrap).scrollHeight;
  const widthPercentage = (unref(wrap).clientWidth * 100) / unref(wrap).scrollWidth;

  sizeHeight.value = heightPercentage < 100 ? heightPercentage + "%" : "";
  sizeWidth.value = widthPercentage < 100 ? widthPercentage + "%" : "";
};

onMounted(() => {
  if (props.native) return;
  nextTick(update);
  if (!props.noresize) {
    addResizeListener(unref(resize), update);
    addResizeListener(unref(wrap), update);
    addEventListener("resize", update);
  }
});

onBeforeUnmount(() => {
  if (props.native) return;
  if (!props.noresize) {
    removeResizeListener(unref(resize), update);
    removeResizeListener(unref(wrap), update);
    removeEventListener("resize", update);
  }
});
</script>

<style lang="less">
.scrollbar {
  position: relative;
  height: 100%;
  overflow: hidden;

  &__wrap {
    height: 100%;
    overflow: auto;

    &--hidden-default {
      scrollbar-width: none;

      &::-webkit-scrollbar {
        display: none;
        width: 0;
        height: 0;
        opacity: 0%;
      }
    }
  }

  &__thumb {
    position: relative;
    display: block;
    width: 0;
    height: 0;
    cursor: pointer;
    background-color: rgb(144 147 153 / 30%);
    border-radius: inherit;
    transition: 0.3s background-color;

    &:hover {
      background-color: rgb(144 147 153 / 50%);
    }
  }

  &__bar {
    position: absolute;
    right: 2px;
    bottom: 2px;
    z-index: 1;
    border-radius: 4px;
    opacity: 0%;
    transition: opacity 80ms ease;

    &.is-vertical {
      top: 2px;
      width: 6px;

      & > div {
        width: 100%;
      }
    }

    &.is-horizontal {
      left: 2px;
      height: 6px;

      & > div {
        height: 100%;
      }
    }
  }
}

.scrollbar:active > .scrollbar__bar,
.scrollbar:focus > .scrollbar__bar,
.scrollbar:hover > .scrollbar__bar {
  opacity: 100%;
  transition: opacity 340ms ease-out;
}
</style>
